As the wise man once said “necessity is the mother of invention”.
I’m sure that it will take you no time to build a “tool” to solve your problem. What about employing one more PIC to do the job for you? Set it up to count incoming pulses from your DUT for a set period of time and send the results to a LCD or to your preferred PC communication terminal for a visual. You just built yourself a home made, dirty cheap frequency counter ready to solve your problem now and help you in the future.
Just a thought.
Some experimenting and results in that matter were done in the beginning of this thread but unless you are starting with a really high clock flexibility is not that great. I’m not sure if the Assembly approach will bring any more advantage but, again it is out of my league.


Regards,

Nick